Magnetic material



Patented May 6, 1930 UNITED STATES PATENT OFFICE GUSTAF w. ELMEN, 0F LEONIA, NEWJERSEY, 'ASSIGNOR 'ro BELL TELEPHONE LAB- ,OBATORIES, INCORPORATED, 013 NEW YORK, N. Y., A CORPORATION OF NEW YORK MAGNETIC No Drawing.

This invention relates to magnetic co1n fp0s1t1ons having desirable combinations of properties, substantially high initial permeability, high rcsistivity,'good constancy of permeability and magnetic stability.

Nickel-iron alloys of high initial permeability and high permeability at low ma gnetizing forces are well known, as are also a number. of such compositions including various constituents for increasing the resistivity. Such compositions in general have not ordinarily possessed good constancy of permeability combined with high resistivity.

Alloys of nickel, iron and cobalt with fourth substances added to increase the resistivity are also known and these compositions have a high degree of constancy of permeability when properly treated, but they have a'tendency to lose their constancy of permeability or otherwise change their magnetic characteristics under the influence of moderately high magnetizing forces.

Others have claimed to have produced alloys including aluminum and/ or silicon Application filed April 2,

ATERIAL having favorable values of the properties herein discussed.

A feature of the present invention comprises magnetic compositions not including aluminum or silicon suitable for loading of telephone conductors both of the deep sea and paper insulated cable type. {They arealso of utility for cores of loading coils and other magnetic structures requiring high resistivity, moderate permeability, fair constancy of permeability and stability. In the following list is set forth a number of typical compositions with initial permeabilities, generally the average of three determinations, and perccntage of change in permeability at specifled magnetizing forces. in gauss, likewise given asthe average of three determinations. The'resistivity in microhm ems. is also indicated. Where fractional percentages of com position are, given the composition has been determined by chemical analysis, where whole percentages of composition are given the figures indicate the attempted composition by weighing the constituentsused in the mixture. The list follows;

1 Hatwhlch Percent Percent Per cent Percent Per cent Per cent Percent Percent Reeisf: cent per cent an chan ein N1 Fe Mo 01- Cu v w Mn ma F j med 4 1500 50. 5 2. e .0107 ii' i2 10 1200 96.85 2.10 .0230 30 01 a 905 84. 8 a. 25 0257 1 59.54 50.37 5.30 .51 1435 70.5 5.42 .0180 45. 97 51. 1s 2. 87- I 1847 7a 1. 70 0215 45.83 47.05 5.88 r .57 2100. 85.6 3.20 V .0178 45 45 10 1015 88 1.12 .0238 55 59 8 1174 71.7 1.50 .0238 55 55 10 1134 25. 5 1. 90 .0230 85 29 8' 1847 78 3.33 .0179 55 a5 10' 813 100.5 1.34 .0220 49 0 634 91 2.17 .0411 50 32 10 8 789 103 2.10 .018 05 20. 0 1855 51.4 2.40 .024 05 29 0 1141 89.6 1. 84 .0170 50 a2 10 1256 98. s s. 05 01s 45 54 1 1871 53.4 5.90 .012 45 52 5 1079 74 3.82 .012

All the above specimens'gjwcre heat treated by placing in an annealinggpot having a rim higher than the cover around the edge upon which was placed finely divided iron for pro- 5 tecting the specimens against oxidization.

They were maintained in an-annealing furnace at about 1000' C. for one 'hour and cooled slowly to room temperature in the furnace. Each specimen consisted of a nari row tape, a fraction of an inch wide and a few thousandths of an inch'thick wound into a ring.

It will be noted that although they differ somewhat in their properties, all these compositions are characterized by a high value of initial permeability, a high or fairly high resistivity and a very good constancy of permeability over the range investigated. Compositions having these properties to the ex- 2 tentindicated in the table are deemed to be quite desirable for the loading of telephone conductors.

What is claimed is:

1. Amagnetic composition having between and 70% nickel, an amountgreater than an impurity and Icssthan 20% of material for increasing the resistivity and thehala'nce iron, with a negligible or zero content of met als of atomic weight under 30, characterized 30 by a specific resistance of-not less than 50 microhm ems, an initial permeability in excess of 500, and a constancy of permeability such that thepermeability at a magnetizing force of .01 gauss does not difier by as much as as 6% from the initial value.

2. A composition in accordance withclaim 1 in which the resistance increasingmaterial includesnot'in excess of 12% of the total compositionof material selected from a group 40 of elements including chromium, molybdenum and tungsten.

In witness whereof, I' hereunto subscribe my name this 1st day of April, 1929.

GUST-AF W. ELMEN. v V 

